Re: PageGetMaxOffsetNumber

On Sun, 15 Dec 2002 23:49:57 -0300, Alvaro Herrera
<alvherre@dcc.uchile.cl> wrote:
>PageGetMaxOffsetNumber (the upper bound) returns a consistent value
>that's far too high (4294967291, 0xFFFFFFFB)

Alvaro, maybe this comment from bufpage.h can shed some light on it?

/** PageGetMaxOffsetNumber*  Returns the maximum offset number used by the given page.*  Since offset numbers are
1-based,this is also the number*  of items on the page.**  NOTE: to ensure sane behavior if the page is not
initialized* (pd_lower == 0), cast the unsigned values to int before dividing.*  That way we get -1 or so, not a huge
positivenumber...*/
 

#define PageGetMaxOffsetNumber(page) \ (((int) (((PageHeader) (page))->pd_lower - SizeOfPageHeaderData)) \  / ((int)
sizeof(ItemIdData)))

0xFFFFFFFB is -5.
With SizeOfPageHeaderData == 20 and sizeof(ItemIdData) == 4 you get
this result for pd_lower == 0.

ServusManfred